>>1913648The fact that it's shimano is good, even if you get one of their low-tier parts replacement shit will be easy to come by.
Honestly unless you got some pictures to share of the components themselves (closeups of the gears and shit) you're probably safe to go and buy that bike.
That is, like I said, if it shifts and brakes well. Know that a bike only shifts if you're pedaling, so don't try to shift while sitting on the bike stationary.